SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c70788c66e67fc2906f4ab045175b3e439e9fda04c861e1a2b683360b2d3fa88' 
  AND token = 'Ae8Gv3CI6Ri/XTuhl1Nw1wUCPNJmnn9yYVOQJh1OVOg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}